The present invention relates to a polygonal cutting bit for cutting tools for machining work, the bit being of the type provided with raised chip forming elements.
In prior art cutting bits of this type, chip breaker grooves are formed along the cutting edge in which, for example according to a proposal made in German Pat. No. 2,309,443, chip breaker projections are provided in the form of a plurality of spaced juxtaposed spherical segments.
The chip breaking capability and the working strength of the above-described cutting bit are not necessarily satisfactory.
Accordingly in the U.S. Pat. No. 4,214,845 throw away inserts have been proposed, which have hemispherical chip breaking projection means extending from each of said cutting edges downwardly towards the center of at least one of the major surfaces of the insert body.
However, it has been found in practice that the above-described cutting bits can be used only within limits for different cutting conditions such as different cutting depths, feed rates and cutting rates, and for certain materials. In the course of industrial development and particularly due to increased automatization, it has become necessary, however, to have the most universally employable cutting bits for which the reliable shaping and removal of chips from the machine is a primary prerequisite for continuous operation.